Very interesting thread. 
First, Phate, you mentioned that your protein has about 1g of carbohydrate; and therefore, causes no change in insulin. Correct me if I'm wrong, but protein (including whey) causes a fairly large raise in insulin - just by itself. Your pancreas isn't only responsive to carbohydrates.
correct though there isn't a significant increase in comparison to carbohyrates i believe
Human insulinotropic response to oral ingestion of native and hydrolysed whey protein.
Power O, Hallihan A, Jakeman P.
Human Science Research Unit, Department of Physical Education and Sports Science, University of Limerick, Limerick, Ireland, [email protected].
The insulinotropic response to the ingestion of whey protein and whey protein hydrolysate, independent of carbohydrate, is not known. This study examined the effect of protein hydrolysis on the insulinotropic response to the ingestion of whey protein. Sixteen healthy males ingested a 500 mL solution containing either 45 g of whey protein (WPI) or whey protein hydrolysate (WPH). The estimated rate of gastric empting was not altered by hydrolysis of the protein [18 (3) vs. 23 (3) min, n = 16; P = 0.15]. Maximum plasma insulin concentration (C (max)) occurred later (40 vs. 60 min) and was 28% [234 (26) vs. 299 (31) mM, P = 0.018] greater following ingestion of the WPH compared to the WPI leading to a 43% increase [7.6 (0.9) vs. 10.8 (2.6) nM, P = 0.21] in the AUC of insulin for the WPH. Of the amino acids with known insulinotropic properties only Phe demonstrated a significantly greater maximal concentration [C (max); 65 (2) vs. 72 (3) muM, n = 16; P = 0.01] and increase (+22%) in AUC following ingestion of the WPH. In conclusion, ingestion of whey protein is an effective insulin secretagogue. Hydrolysis of whey protein prior to ingestion augments the maximal insulin concentration by a mechanism that is unrelated to gastric emptying of the peptide solution.
PMID: 18679613 [PubMed - as supplied by publisher] 
Also, in contrast to you all who feel "shitty" after a fasted cardio state, I do not. My head actually feels clearer and I'm more focused it seems. After some research, this could be attributed to increased catecholamine activity. To each his own... but that is my own experience.
i agree with this
Another point I would like to raise: from what I have read, your body will metabolize stored glycogen, fat, or amino acids (muscle) for energy. From these three primary energy sources, your body will take the path of least resistance and use glycogen first, fat second, and muscle third. Now I'm not saying your body is run exactly like a car and once one tank is empty *ding!* it moves on to the next. But from a general point of view, glycogen is mostly depleted (after eight hours of sleeping, glycogen in the liver is almost all metabolized), then low intensity aerobic exercise would cause the body to metabolize adipose tissue as energy. 
this is mostly correct, but we are assuming here that we stay in an aerobic state the entire time and that all other variables are accounted for(hydration and such), i read a study a while ago that showed that only 60 something percent of energy use during glycogen depleted cardio was fat, so what was the other 30 something percent, i'll try to find the study
With supplemental BCAA's (as previously mentioned by Phate: "BCAA's are catabolized in the skeletal muscle of the body (therefore bypassing the liver). Skeletal muscle contains enzymes that break down the BCAA's & utilize there energy) that fasted state cardio could be beneficial. 
Whether or not BCAA cause any insulin response, I do not know (does anybody know the answer to this?) but point in case, raised insulin levels would blunt the effects of adipose oxidation. 
bcaas are insulinogenic, but i don't think the spike is that much
Anyways, that's my two cents. I seem to be the Devil's Advocate here lol.